CVE-2025-5803 is a missing authorization vulnerability identified in the VikBooking Hotel Booking Engine & PMS, affecting all versions up to and including 1.8.2. This vulnerability arises because the application fails to properly enforce authorization checks on certain sensitive operations, allowing an attacker with low-level privileges (PR:L) to perform unauthorized actions remotely over the network (AV:N) without requiring user interaction (UI:N). The vulnerability impacts confidentiality, integrity, and availability (C:H/I:H/A:H), meaning an attacker could potentially access sensitive customer data, modify booking information, or disrupt hotel management operations. The scope is unchanged (S:U), indicating the exploit affects resources within the same security scope. Although no public exploits have been reported yet, the high CVSS score of 8.8 indicates a critical security risk. The vulnerability was reserved in June 2025 and published in November 2025, with no patches currently linked, suggesting organizations must proactively monitor vendor updates. The VikBooking system is widely used in the hospitality industry to manage reservations and property management, making this vulnerability particularly impactful for hotels relying on this software for operational continuity and data protection.

For European organizations, especially those in the hospitality sector, this vulnerability could lead to unauthorized access to sensitive guest information such as personal identification and payment details, resulting in data breaches and regulatory non-compliance under GDPR. Attackers could manipulate booking data, causing operational disruptions, financial losses, and reputational damage. The availability impact could lead to denial of service conditions, affecting hotel operations and customer experience. Given the hospitality industry's importance in countries like Spain, Italy, France, and Germany, the threat could have widespread consequences. Additionally, compromised systems could be leveraged for further attacks within the network, amplifying the risk. The lack of user interaction and low privilege requirements lower the barrier for exploitation, increasing the likelihood of attacks if unmitigated.

Organizations should immediately audit access controls within VikBooking PMS to ensure strict role-based permissions are enforced, minimizing low-privilege user capabilities. Network segmentation should isolate the booking engine from broader internal systems to limit lateral movement. Implement comprehensive monitoring and alerting for unusual access patterns or unauthorized changes in the booking system. Until an official patch is released, consider deploying web application firewalls (WAFs) with custom rules to block suspicious requests targeting authorization bypass attempts. Regularly review and update credentials and restrict administrative access to trusted personnel only. Engage with the vendor for timely patch releases and apply updates promptly once available. Conduct penetration testing focused on authorization controls to identify and remediate similar weaknesses proactively.